Late Fathers PT-422: What should I do with it?

[3rd Coast]

Time to change the air filter?

Air filter is new, forgot to mention that.

 

[3rd Coast]

I'm wondering if a valve is sticking. Try a good dose of Sefoam and Marvel Mystery Oil.

My dad always thought it was a valve issue. What causes a valve to stick?

I see in the manuals it calls for a carbon cleaning on the heads at a certain hour range.

 

[oldnslo]

Most common cause of valves sticking is carbon buildup. Usually more of a problem on exhaust valves but it can be on either.

This problem gets worse if valve guide allows oil to work past into combustion chamber.

 

[MossRoad]

….

The good: It seems to run well most of the time. We've had a field day with it at home burying drain lines, moving trailers, and digging fence posts.

…

I really love this thing and am considering selling my larger Kioti tractor instead of selling this. Seems to be a better all around tool for my small homestead.

Edit: Machine has about 720 hours.

Keep the Kioti around for a while, get the PT running well, and do comparable jobs with them both. There are some things the tractor will do better when it comes to pulling tasks. But I’m glad you found the PT useful.

I kept my IH2500b for 10 years after we bought the PT. I never found a good reason to keep it for the tasks that we do once we got the little PT425. So, I sold the IH. The very few times I could use the IH, I just cut the task in half and do it with the little machine.

For us, lawn mowing is the main task, followed by snow removal, brush cutting, mulch and material moving, digging the occasional hole, and firewood harvesting. If I had to plow dirt or pull stumps, I’d probably get a conventional tractor. If I had to load dump trucks or move logs around for lumber, I’d probably get a larger PT model.

Anyhow, hope you get the thing running well and put it through more tasks.

 

[Tony H]

Sounds like a Lean running condition. Not sure how long it sat. I'd check fuel lines from tank to filter to carburetor. I'd also backblow gas line up to gas tank and see if the fuel tank is full of crud.

Carbon buildup can be cleaned up by DRIPPING water down the carburetor as the warmed up engine runs. CAUTION: too much water at one time can cause hydro lock.

 

[ponytug]

My dad always thought it was a valve issue. What causes a valve to stick?

I see in the manuals it calls for a carbon cleaning on the heads at a certain hour range.

Thanks for updating your saga.

One other item to check is the tappets, to make sure that they are straight.

Valve adjustment is straightforward, and worth doing if for no other reason than to eliminate it as a possible cause. While you are there, check the valve movement to see that they all "feel" the same. If you have sticky ones, seafoam in the oil and in the gas may help.

Several 425 owners have found crud (e.g. plastic shavings) in their fuel lines, so @Tony H's suggestion of blowing out the fuel line may be worthwhile.

I would have a look around for potential air/vacuum leaks as well.

Please keep us posted!

All the best,

Peter

 

[3rd Coast]

Today i changed the oil and filter. I also decided to drop new plugs in it since I had to head to the store for 10w-40 anyway. They didn't have the Robin factory spec NGK 6ES. The plugs I pulled out were NGK 4ES. Store didn't have either so I took a cross ref'd AC Delco plug.

The Robin was very hard to start and immediately backfired rapidly once I added any fuel. I pulled the plugs out and popped back the old 4ES. She started right up and ran fine. The 4ES looked fine if maybe a tad lean.

I'll pull fuel hoses next. Good ideas.

 

[Spanky100]

3rd Coast

Glad to hear you have your Father's PT at your home and are making progress with getting the engine issues sorted out. This very helpful group will help you get it running well over time. The worst case would be a engine change/upgrade.

Sounds like the PT-422 would fit your needs well. As you make the decision if you will keep or sell the PT my experience is the few things that I have from my Father and Grandfather bring additional joy to myself and children during use as we recall the memories of earlier generations using the same equipment. The PT-422 is a solid and simple to maintain effective tool that can last many generations if it is taken care of. Last year I gave my son the Cub Cadet Lawn Tractor that his Great Grandfather, Grandfather, and I used. He is the 4th generation using it now. His kids, when they get old enough to safely operate it, will be the 5th generation. Not many items can stand the test of time in our throw away economy. The PT sure can.

P.S. Keep the Kioti 2610 if you can. always nice to have additional equipment (toys).

 

[ponytug]

One more thought is that more ethanol has been added to fuel since your engine was originally designed, and your engine may run better on 89 octane. Easy to try.

(Don't forget the SeaFoam in the gas; I would be generous. If you also add SeaFoam to the oil, try to pick a time when you can run it for several hours and then change the oil.)

How to add Sea Foam Motor Treatment to crankcase oil

No Description.

seafoamworks.com

All the best,

Peter

 

[Tony H]

Just a dumb issue I had on an older engine. Does this Robin engine have points and condenser? I had an engine drive me crazy run good one day, an hour later run crummy. Turned out the Condenser fit loosely in the condenser mount. It was getting an intermittent Ground.
How are the spark plug wires?
Is the flywheel rust free as well as the coil(s)?